Implement read & write filter list for stream_get_meta_data()

Implements a 22 year old TODO item.

Author: ndossche

NEWS

@@ -84,6 +84,8 @@ PHP                                                                        NEWS
   . Fixed bug GH-20370 (User stream filters could violate typed property
     constraints). (alexandre-daubois)
   . Allowed filtered streams to be casted as fd for select. (Jakub Zelenka)
+  . Added "read_filters" and "write_filters" keys to stream_get_meta_data().
+    (ndossche)
 
 - Zip:
   . Fixed ZipArchive callback being called after executor has shut down.

UPGRADING

@@ -53,6 +53,8 @@ PHP 8.6 UPGRADE NOTES
     tcp_keepintvl and tcp_keepcnt that allow setting socket keepalive
     options.
   . Allowed casting casting filtered streams as file descriptor for select.
+  . Added "read_filters" and "write_filters" keys to stream_get_meta_data()
+    if the stream has read filters/write filters attached.
 
 ========================================
 3. Changes in SAPI modules

ext/standard/streamsfuncs.c

@@ -507,6 +507,20 @@ PHP_FUNCTION(stream_copy_to_stream)
 }
 /* }}} */
 
+static void stream_fill_filters_array(zval *array, const char *name, const php_stream_filter_chain *chain)
+{
+	if (chain->head) {
+		zval filters;
+		array_init(&filters);
+
+		for (const php_stream_filter *filter = chain->head; filter != NULL; filter = filter->next) {
+			add_next_index_string(&filters, filter->fops->label);
+		}
+
+		add_assoc_zval(array, name, &filters);
+	}
+}
+
 /* {{{ Retrieves header/meta data from streams/file pointers */
 PHP_FUNCTION(stream_get_meta_data)
 {
@@ -535,20 +549,8 @@ PHP_FUNCTION(stream_get_meta_data)
 
 	add_assoc_string(return_value, "mode", stream->mode);
 
-#if 0	/* TODO: needs updating for new filter API */
-	if (stream->filterhead) {
-		php_stream_filter *filter;
-
-		MAKE_STD_ZVAL(newval);
-		array_init(newval);
-
-		for (filter = stream->filterhead; filter != NULL; filter = filter->next) {
-			add_next_index_string(newval, filter->fops->label);
-		}
-
-		add_assoc_zval(return_value, "filters", newval);
-	}
-#endif
+	stream_fill_filters_array(return_value, "read_filters", &stream->readfilters);
+	stream_fill_filters_array(return_value, "write_filters", &stream->writefilters);
 
 	add_assoc_long(return_value, "unread_bytes", stream->writepos - stream->readpos);
 

ext/standard/tests/streams/stream_get_meta_data_filters_list.phpt

@@ -0,0 +1,50 @@
+--TEST--
+stream_get_meta_data() filters list
+--FILE--
+<?php
+
+$fp = fopen(__FILE__, "r");
+stream_filter_append($fp, 'string.rot13', STREAM_FILTER_READ);
+stream_filter_append($fp, 'string.toupper', STREAM_FILTER_WRITE);
+stream_filter_append($fp, 'string.tolower', STREAM_FILTER_ALL);
+
+var_dump(stream_get_meta_data($fp));
+
+fclose($fp);
+
+?>
+--EXPECTF--
+array(11) {
+  ["timed_out"]=>
+  bool(false)
+  ["blocked"]=>
+  bool(true)
+  ["eof"]=>
+  bool(false)
+  ["wrapper_type"]=>
+  string(9) "plainfile"
+  ["stream_type"]=>
+  string(5) "STDIO"
+  ["mode"]=>
+  string(1) "r"
+  ["read_filters"]=>
+  array(2) {
+    [0]=>
+    string(12) "string.rot13"
+    [1]=>
+    string(14) "string.tolower"
+  }
+  ["write_filters"]=>
+  array(2) {
+    [0]=>
+    string(14) "string.toupper"
+    [1]=>
+    string(14) "string.tolower"
+  }
+  ["unread_bytes"]=>
+  int(0)
+  ["seekable"]=>
+  bool(true)
+  ["uri"]=>
+  string(%d) "%s"
+}